Liquid level control



www1@ P. F. SHN/Emi LIQUID LEVEL CONTROL Filed May 19, 1952 INVENTOR. PAUL E SHIVERS ATTORNEY Patented Apr. 13, 1.954

UNITED STATES iATENT OFFICE LXQUD LEVEL CONTROL Paul F. Shivers, Edina, Minn., assigner to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application May 19, 1952, Serial No. 288,586

l Claims. 1

This invention relates to a liquid level control and, more particularly, to an oil level control device for maintaining a constant oil level with respect to an oil burning furnace and for controlling the iiow of oil thereto.

The prior art devices for maintaining a constant oil level with respect to a furnace, which are being used commercially, are of the type wherein a oat is used to control a valve, to maintain a predetermined constant oil level. This type of control is satisfactory so long as the float, which is usually of the hollow ball or sheet metal chamber type, remains buoyant. However, when the oat of this type springs a leak, the inlet valve controlled thereby opens and the device is hooded with oil and, unless suitable safety means is provided, the oil will flow over into the space in which the furnace is located. If an additional safety mechanism is provided, such as a second oat to actuate the inlet valve to its closed position in the event of such flooding, the control device becomes quite large and expensive.

It is an object of this invention to provide a liquid level control device which is compact, inexpensive, durable, and which will fail-safe in the event that the power means for actuating the inlet valve fails.

Another object of the invention is to provide a control device for maintaining a constant liquid level, which makes use of the principle of heat dissipation by the oil to regulate the opening and closing oi an inlet valve by a heat motor.

Still another object of the invention is to provide a liquid level control wherein an electrical current constantly passes through a bimetallic member to actuate an inlet valve and in which the actuation of the valve is controlled by the cooling of the bimetal in response to liquid level in the device.

Still another object of the invention is to provide a liquid level control device having a U-shaped bimetal valve actuator extending at an angle across the liquid level line so that slight liquid level variations will provide substantial, but not sudden, variations in the heat dissipation from the bimetallic member when electric current is constantly passing therethrough.

A still further object of the invention is to provide a liquid level and liquid flow regulator making use of a constantly heated bimetal, for

controlling the liquid level valve, and a thermostatically controlled heat motor, for regulating or controlling the delivery valve of the device.

Still other objects of the invention will become apparent upon reading the following detailed description of the invention in conjunction with the accompanying drawing wherein:

Figure l is a side elevation view of the liquid level control with a portion of the side wall thereof broken away;

Figure 2 is a plan view with portions thereof broken away; and

Figure 3 is a cross-sectional view of the control taken along line 3-3 of Figure 1.

The invention is illustrated as comprising a generally cup-shaped body II divided into two open-top chambers l2 and I 3 with a dividing wall lil therebetween. Located under the chamber I2 is a lter chamber I3 having an internally threaded inlet passage IB and a removable valve seat I'i positioned between the chamber l5 and chamber I2. A removable lter IB, having an end plug member I9 is held in assembled relationship in the chamber I by means of :a clamp bar 26. One end of the bar 2D rests on a notched boss 2l while the other end of the bar rests on the member I9. A bolt 22 extends through the bar and is screw threaded into body II to clamp the bar 20 tightly against the boss 2I and plug I3 to sealingly hold the plug against the body.

Cooperating with the valve seat Il, is a valve 23, which has a stem 24 vertically slidable in a bore 25 through a mounting plate 26. The plate it is secured to the dividing wall I4 by means of screws 2l. A compression spring 23 normally biases the valve 23 into seating relationship with the valve seat I' to prevent the flow of oil into the chamber I2. Transversely offset and positioned below the plate 2E, is an arm extension 28a. The arm 25a is adapted to be pivoted about the base of the arm, against its inherent resilience, by means of an adjusting screw 213, screw threaded through the free end of the arm 26a. The lower end of the screw 29 is swivelly mounted in a socket in the bottom of the chamber I2.

Secured to the arm 26d by means of electrical terminal bolts 3c, which are insulated from the arm 26a by washers 3| of suitable insulating material, is a generally U-shaped bimetallic arm 32. The spaced ends of the open end of the bimetallic arm are rigidly secured on the bolts 30 by means of nuts 33 and 34 while the closed movable end of the arm 32 is bifurcated to fit in an annular groove (not shown) in the valve 23 for moving the valve between opened and closed positions, depending upon whether the arm 32 isnt or is, respectively, suiciently cooled by the level of oil in the chamber I2. Leads 35, clamped v3 between nuts 36 and 3l on each of the bolts 30 extend to the secondary coil or a transformer .33 positioned in the chamber i3. The core of the transformer 38 is shown at 39 in the drawing while the line voltage lead to the primary coil of the transformer is shown at im. The transformer is held in its assembled position in the chamber i3 by means of a downwardly extending arm il engaging the top of the core of the transformer at one end thereof and secured to the wall of the body Il and the partition wall ill by means of bolts 42.

When the control is installed in a heating system, line voltage current will be constantly supplied to the transformer 3s which, in turn, constantly supplies lower voltage current to the U-shaped binietallic arm 32 which is in series relationship with the secondary coil. When there is insufficient oil in the chamber i2 to dissipate the heat from the bimetal arm 32, said arm will warp in a direction to move the valve engaging end thereof upwardly to open the valve 23 against the Vbias of spring 28. Then, after oil has been admitted to chamber i2. to a predetermined oil level substantially half-way up the arm 32, the

heat in the arm will become suiiiciently dissipated to the oil, from the oil to the valve body Il, and from 'the body il to the atmosphere, to cause the arm @t to warp in adirection to close valve 23. The valve will remain closed so long as the oi level remains at the predetermined level, which may be varied by adjusting the screw 29 to pivot the arm lita upwardly or downwardly and thus change the relative position of the arm 32 and valve 23 with respect to the valve seat il'.

The oil is discharged from chamber l2 to a furnace through internally threaded outlet passage member fili, which is controlled by a valve dll of conventional construction. The valve 44 is biased toward its open position by means of compression spring iii extending between the bottom of chamber iii and a fixed annular shoulder Mia on the valve member' de. The valve it is normally held in its closed or minimum flow position by means of a bimetallic arm i6 on which is mounted a heater wire di. One end of the bimetallic armio is secured to a bracket 48. The bracket, in turn, is pivoted on a pivot pin Si in a block 5t?, suitably secured to the mounting plate 2t. Secured to the top of the block 5U by means of screws ci, is a short rigid plate 52 and a long rigid arm 53. An adjusting screw 5d extends through a large hole 53h in the arm 53 and is screw threaded through the plate 52 and into abutting` relationship with the bracket 48. The screw 5s is adjustable to cause a portion of the arm 4E, near the free end thereof, to bear against the valve ill to hold said valve either in its closed position or in its minimum fiow position against the bias of spring 45. The minimum flow position of the valve is determined by an adjusting screw 55 screw threaded through the end of the bimetallic arm 'it for engagement with the tcp of plate [i5 when the valve dll has reached a nearly closed position providing the desired minimum iow of oil for low flame or pilot flame in the furnace. A spring friction clip 5t is provided on the arm it for frictionally holding the adjusting screw 55 in its adjusted position. Access is provided to the adjusting screw 55 through an opening 5l in the arm 53.

The ends of the heater coil il are connected by insulated leads ila and 47h to electrical connector terminals 5t `extending through a panel 59 of insulating` material. The panel 59 is secured to the wall of body ii and partition wall I4 by the same screws i2 that secures member il to said walls.

Energization of the heater 'il to cause opening of the valve fifi is brought about by connecting the terminals to an external thermostatically controlled circuit, which responds to the temperature condition or a space which is to be heated by the above mentioned furnace.

The high flame in the furnace is regulated by limiting the opening or" the valve lll upon enel'- gization or the heater l. This is accomplished by adjustably positioning a control knob @il pivon a shaft 6i extending upwardly from the plate 2i?. The knob is retained on such shaft 6i by means of a screw 62 extending through a hole in the knob and screw threaded into the shaft 5i a spiral bearing surface 63 around the bottom of knob is adapted to bear on an upwardly extending follower 53a on the free end of the arm 53. It is thus seen that by rotation of the knob St, the vertical position of the free end of the arm 53 may be varied. The means for limiting the upward movement ci the valve 44 by the position of the knob lili and arm 53, consists of an adjusting screw 56.1 screw threaded through the arm 53 for engagement with the upper end or 'the valve t4, when said valve has been freed to move under the 1cias of spring 45, by ugoward movement of the arm dii. The adjusting screw @il is adapted to pass through a hole 65 the bimetallic arm it and into engagement with the valve t. Also, the adjusting Screw 64 is frictionally held in its adjusted position by means of a spring clip G6, similar to the spring clip 5t.

Operation The liquid level control device is illustrated in the drawing as being in the condition that it would be in if it were installed in a conventional heating system, with the inlet IS connected to a source of oil, the outlet 43 connected to a pottype of furnace, Vthe primary lead i0 connected to a source of line voltage, and the terminals 53 connected to a room thermostat control circuit and with the room thermostat in a satisfied condition. In such a condition of the control, oil will be supplied to the furnace at a rate sucient to maintain a pilot naine due to the fact thatV the Valve 23 is not completely closed, the lower end of screw 55 being in engagement with the plate 26 to prevent the bimetallic arm 46 from completely closing the valve ed.

Upon a call for heat by the room thermostat closing, the bimetal arrn le will be heated by the energized coil (il to cause saidarm to warp and move the screw 55 upwardly from the plate 2B and the end or valve '34. The spring i5 around the valve will cause said valve to follow the movement of the arm d and move into engagement with the lower end of screw tri extending through the hole Sii, to the maximum flow or high iiame operating condition or" the furnace.

In the event that the outside temperature becomes extremely low or, if for any other reason a greater amount of heat is desired from the furnace than that being provided with the existing adjustment of the control knob, clockwise rotation of the knob will put a deeper portion of the spiral surface over the upper end of follower 53a so as to cause the arm 53 to move upwardly and thus allow the valve :ill to move to a more open position.

-As the oil flows from chamber l2 through the outlet 43, the oil level will fall and thus reduce the icontact area between the oil and the bimetallic arm 432. rIhe smaller the area of oil contact, the smaller will be the dissipation of heat from the bimetal 32. Thus, with a fall in oil level, the bimetal 52 will heat up and move the valve 23 to its open position, where it will remain until the oil level has been reestablished. It will thus be noted that the valve 23 will do some hunting, as long as oil is being applied to the furnace, between its open and closed positions in response to the heating and cooling of the bimetal 32, to maintain a desired oil level. A point of equilibrium is usually established after two or three oscillations of the valve 23, to cause it to admit oil as fast as it is being used. By maintaining a constant oil level in the liquid level control, a uniform rate of flow of oil to the furnace will be maintained regardless of the oil level in the oil storage tanks or other oil supply source.

Failure of the electrical supply causes vaive 23 to close because cooling of bimetal 32 always causes closing of the vaive. This will prevent unsafe burning of fuel when other electrically operated devices of the system are not functioning. Also, ooding of the furnace is limited to the point at which no further oil can now by gravity into the fire pot. At this point the valve closes and remains closed because any rise of the oil level in chamber i2 always causes a cooling of the bimetal 32, which closes valve 23.

As indicated above in the general description of the control, the oil level in the chamber l2 may be adjusted by adjusting the screw 2B. A minimum flow of oil to the furnace for either lowfire or pilot flame conditions, may be controlled by the screw 55. If it is desired that the supply valve be completely closed, upon the room temperature becoming satised, the screw 55 is screwed away from the plate E6 so that bimetal arm 46 can actuate the valve lili to its fully closed position.

While the preferred embodiment of the invention has been described above and illustrated in the drawing, it is deemed to be obvious that Various modifications may be made in the design of the invention and the parts thereof without departing from the spirit of the invention. Therefore, it is contended that the scope of the invention should be determined solely from the appended claims.

I claim as my invention:

1. A constant level oil valve comprising a valve body having first and second chambers therein, an oil inlet valve in said rst chamber, means biasing said valve closed, a rst substantially U- shaped bimetallic member secured by electrical terminal members to an adjustable arm on said valve body near the top thereof, said bimetallic member extending downwardly and laterally into said rst chamber to a point below the normal oil level and having a loose connection at its closed end with said inlet valve, an outlet valve in said rst chamber, means biasing said outlet valve open, a second bimetallic member connected at one end to said valve body and the other end bearing against said outlet valve to hold it closed against its biasing means, an electrical heater positioned to heat said second bimetallic member to move said other end thereof away from said outlet valve to permit it to open, and a transformer in said second chamber with its secondary coil connected to said electrical terminal members for constantly heating said first member.

2. A constant level oil valve comprising a valve body having rst and second chambers therein.

an oil inlet valve in said rst chamber, means biasing said valve closed, a first substantially U- shaped bimetallic member secured to an adjustable arm on said valve body near the top thereof, said bimetallic member extending downwardly and laterally into said rst chamber to a point below the normal oil level and having a connection at its closed end with said inlet valve, an outlet valve in said first chamber, means biasing said outlet valve open, a second bimetallic member adjustably connected at one end to said valve body and the other end bearing against said outlet valve to hold it closed against its biasing means, an electrical heater positioned to heat said second bimetallic member to move said other end thereof away from said outlet valve to permit it to open, and a transformer in said second chamber with its secondary coil connected to said open end of said first member for constantly passing current therethrough.

3. In a constant level oil valve having a valve body with first and second chambers therein, the combination comprising an oil inlet valve in said first chamber, a substantially U-shaped bimetallic member secured by electrical terminal members to an adjustable arm on said valve body near the top thereof, said bimetallic member extending downwardly and laterally into said iirst chamber to a point below the normal oil level and having a connection at its closed end with said inlet valve, an outlet valve in said first chamber, a bimetallic arm connected at one end to said valve body and the other end connected to said outlet valve, an electrical heater positioned to heat said bimetallic arm to move said other end thereof to open said outlet valve, and .a transformer in said second chamber with its secondary coil connected to said electrical terminal members.

4. In a constant level valve, the combination comprising a valve body having a chamber therein, an oil inlet valve in said chamber, means biasing said valve closed, a rst substantially U- shaped bimetallic member secured to an adjustable arm on said valve body near the top thereof, said bimetallic member extending downwardly and laterally into said iirst chamber to a point below the normal oil level and having a connection at its closed end with said inlet valve, an outlet valve in said chamber, means biasing said outlet valve open, a second bimetallic member connected at one end to said valve body and the other end bearing against said outlet vvalve to hold it closed against its biasing means, an electrical heater positioned to heat said second bimetallic member to move said other end thereof away from said outlet valve to permit it to open, and means connected to the open end of said rst member for constantly passing electricity therethrough.

5. A constant level oil valve comprising a valve body having rst and second chambers therein and oil inlet valve in said rst chamber, means biasing said valve closed, a substantially U- shaped bimetallic member secured by electrical terminal members to an adjustable arm on said valve body near the top thereof, said bimetallic member extending downwardly and laterally into said first chamber to a point below the normal oil level and having a loose connection at its closed end with said inlet valve, an outlet valve in said first chamber, means biasing said outlet valve open, a transformer in said second chamber with its secondary coil connected to said electrical terminal members, a bimetallic arm pvy member when constantly heated iby electria-.eui-

.sa-id Valve ata point below! thegxnorma liquid 2,675,019 7 8 oted at one end to said valve body andthe other for actuating the same, said member extending end bearing against said outlet valve to hold it upwardly and laterally from a point below to a closed against its biasing means, an electrical .point above the normal liquid level in saidchamheater positioned to heat said bmetallic arm to ber, an'arm connected at one end to said valve move said other end thereof away from said -5 body; and at the other end thereof to said bioutlet valve to permit it toopen, and adjustable metallic member,. adjustment means for said stop means for limiting the pivotal movement of arm for adjusting said arm and member to vary said bimetallic arm. the Valve closing bias of said member on said.

6. A liquid level. control device comprising a valve, and means for continuously heating said chamber having an inlet valve iol' controlling l0 member suiiicientlyto open said valve When the liquid flow to said chamber, means normally bias- 'liquid level.V is such as to` cause the member to ing said valve to its closed position, a generally heat up and to close sadvalve when the liquid U.shaped bimetallic member ecnnectedto said level is such as to dissipate the heat in Said valve at the closed end of said memberfsaid member.

member extending upwardly-and iaterailyfrom 15 9.a liquid level control device comprising a said closed end at a point below theinormalliquid Ghilmbl havin@ an lt Valve O COltlOllilg level toa point above'the normal .liquid ,lex/elia liquidiiow'to said chamber, a bimetallic member said chamber, astil resilient' arm connected at4 4'ic'enifiectedi`tc valve at one end of said memone end to saidvalve body and. connected. at the ber,Y said member` being positioned at thenormal other end thereof to the open end of :said bi-,l zfliquid Alevel in said chamber with the other end metallic member by insulatedeieetric terminala., l thereof beine iixedlv Supported, said member beadjustment means for. saidtresilie'nt arm.-iorad-y A lpositioned .to y`have: varying.y .surface contact .i tnsaidv liquid as the liquid level thereof .Varies justing said arm andmember to vary the valve Si closing bias of said member' onV said valve,l said andfmeans for-conducting electric cui'rrentto said member. at a constant rate sothat electric our- ;r'ent through said member operates to r .open said valve when the liquid level is such as to cause lthe member to heat up and to close when @the liquid level is such as to dissipate the heat in Soy said member. v

1.10.11 liquid level control device comprising a Acl'lamber having an inlet valve for controlling liquid'iiow to said chamber, a bimetallic member anchored at one end and conneotedto said valve at the other end thereof, said 'member beling-nositioned substantially at the normal liquid level in said chambensaid member extendin in, level 'ill Said Chamber .and arranged i90 be Val'- Wardly and laterallylyrom said closed. @my ,bathed 'by the liquid a5 Che lillllfl level point above the normalliquidievelin sa .isha-liess, and mean' for `conducting electricity ber, a stiff resilient arm, ,eonneeted at e e-vendflogtosaid member constantly for Continuously heatto said Valve body LI-,G nnected at th ,305mg ing thevsaid member so that said member will .operate ,to vopen said valve when the liquid level ber, adjustment meansfor saiuresilient arm for .is Such as t0 Cause the member to heat un and adjusting said armfandmembel@ to tary, V toy close when theliquid level is such as to dissiclosing bias of saidmemberorisaid llave, said, 5' pat@ he hesullpled t0 Said member-n. ,Y member when constantly heatedby electricjcur- Y rent passing therethrough bemgnperabtogopen RQQIQHCES Cited ln the file O JlhS 13a/tent said valve when theliquid'level is such aste- Clauser A UNLTED STATES vPATENFS the member to heat up and to close when the Number i Name Date rent passing therethrough being operable to :OneT- said valve when the liquid level is. suchfa to cause'the member to heat up and to close when the liquid level is such as to `.dissipate theheat generated in said member.

7. A liquid level control device com Y chamber having an inlet. valve for cor-"- liquid now to saidchamber, means norm ing said valveto its closed position,y a b me member having one end thereoiA conn ted.

liquid level is such as todissipate the heat "gene ,5G 2,1.1g443' Mecorlde May 24 1938 eratd in Said mmbel'; "fuf 2;,143277 McCorkle Jan. 1G: 1939 8. In a liquid level' control device, t efcom- 'I 2,211,301 Taylor Aug. 13, 1940 bination comprising fa chamber-havin inlet v22745145 Johnson Feb. 24, 1942 valve for controllingfliquid"flow to said chain-,- 22,409,112 Dillman Oct. 8, 1946 ber, a blmetallic memberjeonneted tofs" 'a valve 55 J 2,526,069 Douglas oet. 17, 195o 

